Machine tool bed



FIG. 1 is a front and right side perspective view of a machine tool bed showing our new design;

FIG. 2 is a rear perspective view;

FIG. 3 is a front elevational view;

FIG. 4 is a bottom plan view;

FIG. 5 is a right side elevational view;

FIG. 6 is a left side elevational view; and,

FIG. 7 is a top plan view thereof. 

The ornamental design for a machine tool bed, as shown and described. 